[Peak expiratory flow rate in 4- to 15-year-old children. Comparison of 3 measuring models].

OBJECTIVE: a) To establish the possible differences between three different models of PEF-meter, including PF-Control for the first time; b) to build a normogram for each of the three models, as a function of different variables (age, height, and inspiratory and espiratory thoracic circumference); c) to search for differences between both sexes, and d) to study the mathematical correlation between the results yielded by the different models.

METHODS: PEF was measured in a sample of 476 school-children, in the range of 4 and 15 years (233 boys, 243 girls), with a mean age of 9,3 years and a height range between 96,8 cm and 178,8 cm (mean 137,9). PEF value was recorded as the best of three attempts when the difference them was less than 10%. Three devices of each model were used (Vitalograph, Mini-Wright, PF-Control). The utilisation was always done in a rotatory fashion at school time (15-17 hours) in the children's school.

RESULTS: We found significant differences between the three models (p < 0,0004). The best predictive variable for PEF is height, with an r = 0,90-0,92 (depending on the model) when the exponential model is considered. Independently of the device, there were significant differences between sexes.

CONCLUSIONS: a) The variable that expresses PEF the better is height; b) PEF values are different between girls and boys; c) there were significant differences between the various models; d) Monitoring of a given child must be done with the same model of PEF-meter, and e) The best correlation is obtained with the exponential model, although differences with the lineal model were not statistically significant.